At present, the transmission network technology is mainly divided into a synchronous digital hierarchy (SDH) technology and a wavelength division multiplexing (WDM) technology, and each technology has its own advantages and disadvantages: the SDH technology mainly processes electrical layer signals, and has the advantages of flexible scheduling, rich protection functions and complete operation administration and maintenance (OAM), but the bandwidth it provided is limited, which can not meet the growing service needs. The WDM technology can provide a large-capacity bandwidth through the multiplexing of wavelength, but it can not provide the flexible scheduling and rich protection functions because the immature of optical layer processing. Based on the advantages and disadvantages of the SDH and the WDM, the International Telecommunications Union-Telecommunications standardization sector (ITU-T) provides an optical transport network (OTN) system architecture which synchronously has the advantages of the SDH and the WDM.
However, the introduction of the OTN device brings another problem: a multiple layer network (MLN)/multiple region network (MRN) problem. In the generalized multi protocol label switching (GMPLS) network, one switching capability is defined as one region, and a converged network with multiple switching capabilities is the MRN. And a network with different rates under the same switching capability is the MLN. The OTN network is a typical MLN/MRN which contains two switching capabilities, that is the time division multiplexing (TDM) and the lambda switching capability (LSC). Wherein, the switching capability of an optical data unit k (ODUk) layer is TDM, and the switching capability of an optical channel layer (OCh) is LSC. In the ODUk layer, as the values of k are different, the service rates are different, e.g., ODU1 is 2.5 Gb/s, ODU2 is 10 Gb/s. Thus the ODUk layer network is an MLN.
In the OTN device, as there are two switching capabilities which are the LSC and the TDM, when a service is switched from a port of one switching capability to a port of another switching capability, it needs to judge according to the adapter capability between these ports, if the adapter capability meets the requirements of the service signals, the switching succeeds, and if not, the switching fails. At present, related extensions exist in the standard protocol, and in the draft-ietf-ccamp-gmpls-min-extensions, a structure for describing the switching capabilities, i.e., interface adapting capability description (IACD), is defined. But the adapter capability between the OCh and ODUk layers in the OTN device is not completely described in IACD, so the adapting information between MRNs is not very accurate when being described by the IACD, therefore the route calculation results can not be guaranteed.
Aiming at the problems of the related art that the adapting information between MRNs is not very accurate when being described by the IACD because the adapter capability of the OCh and ODUk layers in the OTN device is not completely described by the IACD, therefore the route calculation results can not be guaranteed, there is not yet an effective solution.